Fired ceramic having dense and low thermal expansion characteristics

Abstract

A fired ceramic having dense and low thermal expansion characteristics comprises 0.3 to 8 wt. % of at least one of rare earth oxides and has a thermal expansion coefficient of less than 0.3% and a porosity of less than 10%. The fired ceramic having dense and low thermal expansion characteristics comprises a main component of cordierite, lithium aluminosilicates or aluminum titanate. The rare earth oxide is preferably Y2O3 and can be CeO2 or La2O3.

What is claimed is: 
     
       1. A fired dense ceramic possessing low thermal expansion characteristics, consisting essentially of: from 0.3 to 8 wt. % of at least one rare earth oxide selected from the group consisting of Y 2  O 3  and CeO 2  in cordierite, said fired ceramic having a thermal expansion coefficient less than 0.3% at 25° C. to 1000° C. and having a porosity less than 10%. 
     
     
       2. The fired ceramic according to claim 1 wherein the rare earth oxide is Y 2  O 3 . 
     
     
       3. The fired ceramic according to claim 1 wherein the content of the rare earth oxide is in a range of 1 to 4%.